1. Field of the Invention
The present invention relates to a magnetic substance holding device, and more particularly, to a magnetic substance holding device that controls permanent magnet energy with which it is possible to obtain a strong holding force with a simple structure and to change from holding to releasing and vice versa by using only a low current.
2. Description of the Related Art
A magnetic substance holding device such as a permanent magnet workholding device is used to attach a target made of a magnetic material such as iron by using a magnetic force, and is widely used in various areas as an internal device attached to a die clamp of an injection molding machine, a die clamp of a press, a chuck of a machine tool, or the like, nowadays.
Basically, the magnetic substance holding device attaches the target formed of a magnetic substance to a holding face by using a strong magnetic force of a permanent magnet. When releasing the target, the magnetic substance holding device separates the target from the holding face by controlling a magnetic flow from the permanent magnet so as not to form the magnetic flow to the holding face.
As a method of controlling the magnetic flow from the permanent magnet, a method of controlling the magnetic flow by rotating another permanent magnet that is rotatably disposed and a method of controlling the magnetic flow by using a separate electromagnet may be used.
The applicant(s) has proposed a magnetic substance holding device using a separate electromagnet (see Patent Literature 1).
Patent Literature 1
International Patent Publication No. WO2012/039548A1